In the metallurgical industry of steel and special alloys approximately 90% of molybdenum is used while in the chemical industry and its associated products the amount used is 10%.
Molybdenum is obtained as a by-product of the metallurgical process of copper through selective flotation where it is produced as a natural composite of molybdenum sulphide referred to as molybdenite (MoS2). However, it is required to be in high purity oxide or metal state as to be further used in the steel industry, mainly.
The metal is used as a ferrous-molybdenum alloy while the oxide used in a direct manner is molybdenum trioxide.
The trioxide is currently produced by oxidizing roast of molybdenite in a cell roasting furnace producing material of the same type and level of impurities than the original concentrate fed into the furnace therein.
The document U.S. Pat. No. 4,523,948 (McHugh et al.) dated Jun. 18, 1985 discloses a method for treatment of molybdenum concentrate in a two-zone roasting furnace in a vertical equipment of twelve (12) stages or levels until molybdenum trioxide is produced in the lower level. The resulting trioxide has the same type and level of impurities that the concentrate originally fed. The method requires a prior or further cleaning process as to remove the rest of the elements. SO2 produced in gases presents a very low concentration for conversion purposes in conventional plants.
Document dock reference CL 39762 (Lusarenko el al.) discloses a procedure for trioxide production by means of microwaves. The document proposes a disc subject to microwaves in order to produce pure trioxide as a more efficient alternative in the different levels of a multi-level roasting furnace. The patent exists but it has a reduced domain without applications.